The restoration of former opencast mining land to woodland : development and evaluation of a GIS-based tool for strategic planting and management
There is a need for models to assist in the planning and implementation of solutions to environmental problems. Given the spatial nature of these problems, there is scope for GIS to be used as a tool to meet this need. The issue of land restoration following opencast mineral extraction is considered. Time and cost constraints usually place restrictions on the quantity of detailed field data that can realistically be collected and analysed on restoration sites prior to planting. This research determines the value of a rigorous analysis of a limited set of empirical data as a means to informing the decision making process. The study site selected is located in northwest Leicestershire. Detailed information is collated to describe the site conditions prior to, and subsequent to, mineral extraction. The presence of an adjacent area of undisturbed woodland affords the opportunity for comparison between natural and artificial soil conditions. Using a combination of field techniques, laboratory analysis, and computer-based modelling, an exploration is made of the factors affecting the success or failure of tree planting within restoration projects. Factors affecting the soil moisture regime are found to play a key role in determining the success of schemes for the establishment of woodland on restored sites. A series of maps are developed to illustrate tree growth potential as constrained by soil thickness and soil structure. Four different 'improvement' scenarios are explored to identify potential areas for remedial action. An analysis of the spatial variation in soil properties can assist in designing planting schemes that reflect the requirements of individual tree species and growth potential indices for alder and larch species are proposed. The hypothesis is accepted that the modelling of soil characteristics can provide additional value to the restoration planning process.